In a letter to External Affairs Secretary Fiona Hyslop, Mr Mundell stresses that the pandas “are a reflection of the strength of our relationship with China” and must be protected.

He also points out that the pandas, named Yang Guang and Tian Tian, were a gift from the Chinese government to the UK Government and that the planning decision is being closely monitored.

In his letter, published following a Freedom of Information request, Mr Mundell also says he will not intervene “at this stage” as planning matters are a devolved issue.

But he adds: “I have asked my officials to continue monitoring this issue with their counterparts in the Foreign and Commonwealth Office and your officials.”

In a sign of the pandas’ importance, Mr Mundell’s letter, dated 13 April, was copied to Mr Johnson and Scotland’s First Minister Nicola Sturgeon, who visited China earlier this month.

The Scottish Government have already told councillors that their decision is of “national importance” due to the possible negative impact on the pandas’ health caused by construction work.

The Corstorphine Hospital redevelopment is being proposed by Sundial Dundas, which wants to convert the listed building into apartments with private car parking and landscaped gardens. However, concerns about the project were raised by the Royal Zoological Society of Scotland, with noise studies being carried out close to the pandas’ pen. A spokewoman for the organisation said: “We have been assured by the City of Edinburgh Council that the wellbeing of our giant pandas will be protected as part of the planning process